Established only 13 years after the first railway station in Japan, the Shinjuku Station was originally a station on the Akabane line, owned by Nippon Railway, the first private rail company in Japan. 24 years later, Shinjuku Station became a station on the Yamanote Loop Line, which took over the previous line.

The Chuo Line, the Keio Line, and the Odakyu Line were added during the following decades, and after the WWII Shinjuku Station was also connected to the subway lines Marunouchi, Toei Shinjuku and Toei Oedo Line. Today, with more than 50 platforms and 200 exits, Shinjuku is the busiest railway node in Japan, and in 2011 was registered by the Guinness World Records as the busiest in the world, with more than 3 and a half million passengers per day.